I have about 2 hrs of flight time on my rex with carbon fiber blades. Everything has been going great until my last two flights. On my previous flight I noticed a small split track maybe 1/4" difference. Today when I spooled up and picked it up to a hover I noticed about the same amount and made some small adjustments to even it out.

Upon entering my first flight pattern the heli began to shake violently and I could see a split track about 1". I landed immediately, looked everything over, noticed nothing but decided I would have to investigate further before flying again.

Tonight I rechecked the CG of both blades and they are dead on each other. I also did a weight check and found one blade to be a tad bit heavier and added about 2 wraps of scotch tape to the lighter blade.

Now upon spooling the heli up I see a split track again of about 1/2" but as I add collective it goes away and blends into 1 perfect track. Once I take the collective out and go back to 0 pitch the split track returns. Does anyone know what is going out and if I'm doing something wrong? I have looked the blades over very well and don't see any damage, defects or separation on them anywhere. I have not crashed or hit anything either.

Bent feathering shaft will cause this too.

Tom..... No "D" flying....

Hey Guys,
Thanks for all your replies. I started at the top of the rotor and started working my way down. I checked the feathering shaft, it rolled very smooth and easy so it was eliminated. Started checking all of the ball joints and sure enough, one of the ball joints on the blade grips was loose. I tightened it up and finished checking the rest. Did a spool up and am very proud to report no split track. I have one solid track all through my ranges.

Just wanted to thank all the feedback that was offered on this. You guys gave me the all right places to check and have got me back in the air again.

The RC discussion world needs to consolidate. RR is now one choice for that.
Its software is cutting edge. It hosts on-topic advertising.
Help RR increase traffic buy making suggestions, posting in RR's new areas (sites) and by spreading the word.